Field of the Disclosure
The present disclosure relates to a method for improving an estimation process, particularly a motion estimation process. The disclosure also relates to a device for providing an improved disparity or motion estimation map, as well as a computer program and a non-transitory computer-readable recording medium.
Description of Related Art
Estimation processes, like motion estimation or disparity estimation, are widely used in image-processing applications. In particular, frame rate up-conversion and the required image interpolation is based on motion estimation results. Some of the best motion estimation algorithms are based on recursive search block matching. The recursive estimation algorithm evaluates a set of candidate vectors which are derived from spatial or temporal predictor positions, which are partially modified based on particular schemes to allow for motion changes, by a matching criterion. However, these recursive search motion algorithms usually have problems with flat or low contrast image contents. One of the reasons is a so-called penalization system used in recursive search motion vector estimation algorithms. The penalization system is for example used to penalize local motion vector changes. The idea behind is that motion vectors inside an object within an image should have the same or at least similar motion vectors. Or in other words, objects are larger than blocks and objects have inertia. Therefore vectors should be similar among blocks in objects.
It has been recognized that such recursive search motion vector estimation algorithms using penalization systems have problems in gaining accurate estimation vectors for flat areas. For example it maybe that a large flat area is assigned with a constant motion vector instead of having a smooth gradient vector field with the result of annoying local judder artefacts in an interpolated image.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.